V70 T5 boost problem

[Mart5in]

Hi I'm Martin! Bought myself a V70 T5, had some issues with it, stupidly got it mapped to 310hp and of course the problems are still there!

Anyways, I've had codes pulled for faulty throttle pedal. removed the connector and reconnected it and they haven't been back for months, although sometimes the cruise control still disables itself as soon as I take my foot off the throttle after setting a speed.

Under load, the car appears fine but it seems to hesistate in the higher rpms and just generally feels a bit down on power especially when trying to hold boost for long periods of time (as you can see from my avatar I do plan on more track days), it's very intermittent.

It's got everyones favourite throttle body on it too, although I noticed that there appears to be a white dot painted on the TPS. Not sure if this has maybe been repaired in the past?

Okay, so the most current "faults" I've had where a code has been triggered. I can only pull generic P codes. I've had boost flow too low, boost flow too high, (not at the same time of course!) long term fuel trim lower limit - I think this last one is probably due to the fact my exhaust isn't in the best of condition. I can't remember the codes but that was the descriptions I have.

So, what I'm asking is, does this point at the MAF? I replaced it with an eBay cheapo. If I disconnect the MAF the car is slower but it boosts consistently slower - of course the idle is all over the place with that unplugged.

Anything else I could check? Boost solenoid and it's pipes? What size of pipe do I need if I change them to silicone?

Do you think my boost and stuttering is a combination of throttle pedal, boost solenoid and cheap MAF?


Thanks in advance

Martin

[Shinsplintz 101]

Stuttering is often down to the ignition system breaking down under load. Check the plugs etc.. & replace anything that you're unsure about.

Boost wise I'd definitely replace the tcv & redo the vac hoses checking for leaks/tears/holes on the main boost pipework from the turbo to ic & back to the tb.

Depends on the history you have with the car as to when items have been replaced in the past , better safe than sorry so if unsure get a good used part or new OE one.

Good luck. Morgan

PS vac hoses are 4mm id, one is 6mm. Use good quality fuel hose, cheap & very effective.

Pps get a good known OE maf & swap it in , that'll give you an idea if your cheap eBay special is faulty.

[stribo]

Hesitation at higher revs could point to a VVT problem, but as above, check plugs and coilpacks first.

[Mart5in]

Thanks for the replies so far!

I've had one of the coil packs changed and all of the spark plugs done a while back. The plugs were totally goosed.

I'll get some hose ordered up, I actually think I have some 6mm in the shed!

I'm gonna step away from the VVT suggestion I've no reason to suspect it unless it's a freak failure. The car has never missed an oil change so no sludge build up etc. lowish miles too. I will keep it in mind.

So what I really need is a known good MAF. What MAF's from other models will fit? There's a few down the local scrapyard I could rob bits off. (2.4 lpt and a bi fuel) and I'm sure there's a couple of S80's in there too but I don't know what engines are in them.

[stribo]

Thanks for the replies so far!

I've had one of the coil packs changed and all of the spark plugs done a while back. The plugs were totally goosed.

I'll get some hose ordered up, I actually think I have some 6mm in the shed!

I'm gonna step away from the VVT suggestion I've no reason to suspect it unless it's a freak failure. The car has never missed an oil change so no sludge build up etc. lowish miles too. I will keep it in mind.

So what I really need is a known good MAF. What MAF's from other models will fit? There's a few down the local scrapyard I could rob bits off. (2.4 lpt and a bi fuel) and I'm sure there's a couple of S80's in there too but I don't know what engines are in them.

Why would you call it a freak failure, the reason I suggested it was because we had the same symptoms with our S60R, also full service history, using better oil than your T5 would have seen. If it's been sat up for a while the solenoid could have seized, or the VVT unit itself. But as said before there are other things to check before the VVT. Also if the VVT was playing up you would get a code, even on a generic reader.

[Craigtange]

Thanks for the replies so far!

I've had one of the coil packs changed and all of the spark plugs done a while back. The plugs were totally goosed.

I'll get some hose ordered up, I actually think I have some 6mm in the shed!

I'm gonna step away from the VVT suggestion I've no reason to suspect it unless it's a freak failure. The car has never missed an oil change so no sludge build up etc. lowish miles too. I will keep it in mind.

So what I really need is a known good MAF. What MAF's from other models will fit? There's a few down the local scrapyard I could rob bits off. (2.4 lpt and a bi fuel) and I'm sure there's a couple of S80's in there too but I don't know what engines are in them.

Are the hoses from the TCV all 6mm? Looking to replace all mine also.

cheers.

[Shinsplintz 101]

No just the 1 iirc, the others are 4mm id.

[mike 850]

definitely try a know good maf not a ebay special

[Craigtange]

No just the 1 iirc, the others are 4mm id.

silly question, what is the iirc, this is on a v70 r 2005.i thought it was all 6mm hoses from the TCV typical i just ordered 6mm ones.

[M-R-P]

I hesitation at high revs and boost could be the engine protecting itself from overboost or lean running (as well as the above possibilities).
A dirty maf can give a throttle position sensor code - don't know why but it can.
It wouldn't hurt to clean or replace the boost pressure sensor as that can cause issues with boost.
What injectors are you running? What condition are they in? If they're not up to the job you'll be running lean.

[Shinsplintz 101]

Iirc- if I recall correctly.

Best way is just to measure the existing pipework, then order the same size. The p2 may well be all 6mm, for some reason I thought the p2 vac tubing was the same size as the p1. Happy to stand corrected. Cheers

[Dream3r]

5mm ID some of it is.

[M-R-P]

It's all 5mn apart from the recirc which is 4mm.

The bigger pipes (evap and brake servo) are 9mn I/d

[Mart5in]

Ahh well, I've no VVT codes.

However today I got a P0101.

Think I'll just chuck my cheap MAF sensor out and get a good OEM one ordered.

[Dream3r]

Go for Bosch OEM maf, also check for leaks everywhere that code can be misleading.

Logging the maf will show you if it at fault.

[Mart5in]

Go for Bosch OEM maf, also check for leaks everywhere that code can be misleading.

Logging the maf will show you if it at fault.

Yeah I know it won't

My friend has bought a 2.3t 850, is the maf the same on that I could use that to diagnose it since it's known working and genuine volvo.

Is it best to go to Volvo for the OEM maf? or is there another place I can get a genuine MAF? I don't trust ebay for genuine stuff, sometimes it's hard to tell.

[Dream3r]

Volvo i'd price against these guys then make your mind p, remember you get discount @ FRF Volvo wit the code C5 http://www.emissioncontrols.co.uk/pa...f%20%20Sensors

IIRC Volvo will be more expensive as they sell the housing and the sensor as once piece..

[Mart5in]

Volvo i'd price against these guys then make your mind p, remember you get discount @ FRF Volvo wit the code C5 http://www.emissioncontrols.co.uk/pa...f%20%20Sensors

IIRC Volvo will be more expensive as they sell the housing and the sensor as once piece..

Thanks, I'll drop them an email.

I'll check EuroCarFarts and see if they have them as well - convenience factor as they're right next to my work.

Yeah I forgot that they sell the whole housing and not just the sensor. How much can they charge for a plastic tube I wonder!


The more I think about the MAF the more it makes sense. I can read the flow rate off it but I'm not sure if my reader will react fast enough. I might go log some data and plot it on a graph. see what it looks like.

[Bones]

When nine was stuttering it was a dodgy Maf, kept throwing a code every now and again but most of the time it was fine, try giving it some stick and it felt like someone was shaking you by the back of the neck!

New Bosch Maf and all sorted!

I did all my hoses aswell, 4mm and 8mm is what I ordered. So now they're all blue and match in with the IPD intake and intercooler pipes.

[Redbrick]

Cheapest place I could find a genuine Bosch MAF was buycarparts.co.uk

Based in Germany and no issues with payment if you use Paypal, Credit card required a photo of the actual card hence why I used papal on the next order.

If you hold it in the basket you get a discount code via Email